1. Technical Field
The present invention relates to a crimp terminal to be mounted to a connector or the like that serves to connect a wire harness for a vehicle, for example, a method of manufacturing the crimp terminal, an electrical wire connection structure and a method of manufacturing the electrical wire connection structure.
2. Related Art
A crimp terminal has a crimp portion to which a conductor of a covered electrical wire is electrically connected. After the covered electrical wire is inserted into the crimp portion, the crimp portion is swaged and crimped to the conductor to thereby connect the covered electrical wire. Such a crimp terminal is used for a wire harness that connects electrical components of a vehicle, for example. The wire harness comprises a bundle of plural covered electrical wires, and a connector is connected to the tip of the wire harness. As disclosed in JP-A-2002-367714, a crimp terminal is connected to the tip portion of a covered electrical wire in a connector. The crimp terminal is connected to a terminal of another electrical equipment or the like.
Increase in number of electrical equipment installed in a vehicle causes increase in number of covered electrical wires. In addition, it is necessary to enhance fuel consumption of vehicles. Therefore, in order to reduce the weight of a wire harness, attention has been paid to change of a core wire of a covered electrical wire from copper to aluminum or aluminum alloy. The weight of the covered electrical wires may occupy 60% or more of the whole weight of the wire harness, and it is possible to greatly reduce the weight by changing the material of the core wire to aluminum-based material.
However, when the copper conductor is replaced by the aluminum conductor, the contact between the crimp portion of the crimp terminal and the conductor is the contact between dissimilar metals because the crimp terminal is formed of copper. That is, the crimp portion is easily corroded when coming into contact with water or moisture. This is called as contact corrosion between dissimilar metals (electrical corrosion). Therefore, in order to enable material change to aluminum with prevention of electrical corrosion, there has been developed a technique of shielding the contact interface between the aluminum conductor and the crimp terminal from the outside with resin material and performing cut-off (water-stopping) performance as disclosed in JP-A-2012-3856 or the like, for example. According to a corrosion preventing structure disclosed in JP-A-2012-3856, after a covered electrical wire is connected to a crimp terminal, a mold portion formed of resin is formed at the connection portion between the crimp terminal and the covered electrical wire.
When a wire harness is used in a vehicle, the usage environment of the wire harness is harsh, so that moisture or dust adheres to the wire harness or the temperature of the wire harness increases. Furthermore, the core wire and the crimp terminal are formed of aluminum-based material and copper-based material respectively, and thus they are connected to each other as the connection between dissimilar metals. Therefore, when moisture or the like adheres to the connection portion between the core wire and the crimp terminal, electrical corrosion such as contact corrosion between dissimilar metals or the like is liable to occur. The electrical corrosion causes contact failure between the core wire and the crimp terminal. The electrical corrosion must be avoided to secure electrical connection of electrical equipment.
Here, it is considered that the core wire is sealed with resin as disclosed in JP-A-2011-233328.